I. Field
The present invention relates generally to transportation and delivery systems, and more particularly, to methods and apparatus for detecting a cargo state in a delivery vehicle.
II. Description of the Related Art
Advances in technology have provided for increased automation in many industries. For example, in the shipping industry, technology has allowed for the shipment and delivery of cargo virtually around the clock. Delivery vehicles now carry and deliver cargo to all parts of the country. For example, in the trucking industry, cargo-carrying tractor-trailers may be driven hundreds or thousands of miles to reach a delivery site. In some cases, a delivery vehicle may make several intermediate stops before reaching its final destination. Thus, it is important to efficiently route delivery vehicles to avoid transporting empty vehicles that may result in revenue losses for the vehicle owners.
Typically, cargo is loaded into a trailer portion of a tractor-trailer delivery vehicle and driven from point to point along a delivery route by a vehicle operator. Along the delivery route, intermediate stops may occur where portions of the cargo are unloaded for delivery or where new cargo is picked up. To facilitate efficient routing, sometimes a trailer is detached from its current tractor and left at a designated location for pickup by another tractor. The trailer may sit at this intermediate location for various lengths of time while waiting to be retrieved by another tractor. This detachable trailer arrangement allows shippers to plan the most efficient and cost effective routes for the delivery of the cargo. In some cases, the trailer acts as a storage container to store cargo for an extended period of time or to allow cargo to be transported via railways.
One problem associated with the delivery of cargo is that it is difficult to accurately determine the cargo state of the trailer portion of a delivery vehicle at any given time. The cargo state indicates whether the trailer is empty or whether the trailer is loaded (i.e., currently contains cargo). The cargo state can be used for several purposes. For example, in one case, the cargo state can be used to determine that the vehicle operator failed to deliver or pickup cargo. In another case, the cargo state can be used to determine that the vehicle operator delivered cargo to the wrong location. Thus, being able to accurately determine the cargo state of a delivery vehicle has become a very important requirement for the shipping industry.
Unfortunately, conventional systems sometimes operate to provide false or inaccurate cargo state readings. For example, temperature, noise, and/or the humidity of the trailer may cause the sensor that is used to measure the cargo state to produce inaccurate results. Additionally, the movement of the trailer, or shifting of the cargo within the trailer may also contribute to inaccurate readings.
Therefore, what is needed is a cargo detection system that operates to accurately detect the state of cargo in a delivery vehicle. The system should operate to overcome the problems associated with conventional systems to provide accurate cargo state information to the vehicle operator and/or remote stations.